This invention relates to thrust bearing arrangements for apparatus having a rotatable shaft about which shaft are arrayed a plurality of axially facing thrust pad surfaces, and in particular to tilting pad thrust bearing arrangements in which individual thrust pad surfaces are able to tilt or rock to a limited extent about a generally radially extending fulcrum ridge.
Tilting pad thrust bearing arrangement are well known per se, having either discrete bearing pads or an integral ring of pads joined to each other by webs of pad material that are thin enough to permit the individual pads to tilt relative to supporting carrier means of the pads and against which, in both forms, the pads bear to transmit axial thrust forces.
The supporting carrier means is formed either as a metal ring of such thickness as to support the thrust loads without deformation or sometimes as a prepared surface of the apparatus housing the bearing arrangement. In either case it is conventional for the pad-supporting face of the carrier means to be substantially flat in the axial direction, except possibly for lubricant nozzles at the surface at locations between adjacent pads, and for the face of each thrust pad opposite to a bearing surface to be machined away except at a central or circumferentially offset location to leave a radially-extending fulcrum ridge by way of which the pad is supported on said supporting face of the carrier means and about which fulcrum ridge it is able to make limited tilting movements.
It will be appreciated that in the case of individual pads or an integral ring of such pads, the provision of such fulcrum ridge on the supported pad surfaces involves an additional and non-trivial manufacturing stage the cost of which may not be fully realised during the life of the bearing arrangement because the machined ridge is upon a consumable item and discarded with any bearing pad that needs replacing due to wear of the opposite, bearing face.
GB-A-1535165 describes a thrust bearing arrangement wherein parallel surfaced bearing pads are supported on a smooth faced carrier by way of an intervening plate machined such that it presents an upstanding fulcrum ridge to each bearing pad. Whereas this construction permits the consumable components, the bearing pads, to be of simpler and cheaper construction, the machined plate nevertheless requires considerable manufacturing effort and, by virtue of its manufacture, has dimensions which add significantly to those of the bearing arrangement.
It is an object of the present invention to provide a tilting pad thrust bearing assembly which is simpler and more cost-effective to manufacture and use.
According to the present invention a tilting pad thrust bearing arrangement comprises a plurality of flat parallel faced bearing pads arrayed about a longitudinal axis and supported on pad carrier means, comprising a carrier body having a flat support face extending about the longitudinal axis and between said support face and the bearing pads support means defining associated with each pad a support member including a substantially radially extending fulcrum ridge about which the supported pad can tilt, each support member comprising a shim member formed by a thin flexible shim material of substantially uniform thickness and each fulcrum ridge by adjacent integral parts of the material overlying each other in face to face contact.